Combining with the diatom-based conductivity transfer function from Qinghai-Xizang (Tibetan) Plateau lakes, the lake salinity for the past 300 years was quantitatively reconstructed based on the analysis of diatom assemblages from a sediment core in Chencuo Lake, southern Tibet. The distinct negative relationship between inferred conductivity and recorded lakelevels in recent years suggests that the lake salinity can reflect the fluctuations of effective moisture of climate in lake area. The salinity inferred from diatoms reveals several major hydrological episodes. An obvious desalination of lake water occurred during the last cold interval of the Little Ice Age (about 1845-1885 AD), indicating a cold and moist climate. The lake salinity presented a rapid increase trend since the middle 1960s, with a peak value and high amplitude of salinity variability in the whole past 300 years. The low effective moisture inferred from the lake salinity may have contributed to the enhanced evaporation by the continuous increase of temperature in recent years.